MicroRNA (miRNA) belongs to the family of non-coding RNAs, which posttranscriptionally regulate gene function. Moreover, accumulating evidence points to an essential role of miRNAs in development and monitoring of kidney disease, though the role of particular miRNAs in patients undergoing hemodialysis is still unclear. This might have consequences. It is possible that measuring a single miRNA in hemodialyzed patients may not provide adequate information about development of many pathological processes. The goal of this review is to highlight the current knowledge in the field of miRNAs, with a special emphasis on their circulation in hemodialyzed patients.